A major problem in amyloid-p peptide (A(3) related research is the inconsistency introduced by the multiple and varied protocols employed by different laboratories for isolating, analyzing, quantifying, preparing and handling Af3; the centralization of procedures within this Core will circumvent these inconsistencies. This Core thus has two specific aims: to provide an A(3 index to each project, and to supply A(3 to each project. Ap index: Different aspects of Ap (concentration, physiological properties, deposition, etc.) are often measured in isolation. To date, a comprehensive assessment of these aspects has not been performed in the same tissue. For each project, Core B will collect and collate, from both human and rodent tissues, the following data: (a) the amounts of Ap (including AP40 and A042) and its solubility, (b) the amounts of oligomeric and fibrillar Ap, and (c) the number of neuritic and non-neuritic plaques. These data will allow the determination of the relationship(s) between individual changes in Ap and the various neurochemical end point measures studied in the different projects. Supply Ap: Evaluation of the physiological properties and toxicity of Ap has been hampered by inconsistencies caused by variability in every possible aspect of Ap handling. Core B will maintain consistency between projects by controlling each of these different variables (peptide acquisition and storage, preparation and quantification of oligomers and fibrils, quantification of toxicity) through adherence to established, standardized protocols and through maintenance of rigid quality control. The novelty of this Core is its thoroughness. We have assembled a unique group of investigators who, together, possess proven expertise for each function of Core B. Utilizing methods that are well characterized and established in their respective laboratories, this team-oriented approach will allow the first comprehensive, multifaceted analysis of Ap in vivo and in vitro. Ultimately, this will provide an unprecedented level of thoroughness and rigor to Ap analysis, imparting much needed fidelity and continuity to project data. First and foremost, the data and materials generated in Core B will allow the individual projects to correlate each of their individual neurochemical alterations to different aspects of Ap assembly, deposition and toxicity.